is it possible to lower the gain further? using my custom IEM's and both the marked resistors clipped, i still get VERY little play in the volume knob until it is too loud. these are very sensitive IEM's.
thanks

Clipping the resistors is to change the gain to unity (no gain). You can't really reduce it from that without some type of transformer or voltage divider circuit somewhere along the line. The simple hiss buster circuit linked would be one of those voltage dividers.

Just turn the volume down in software. You have an ODAC after all, with 24-bit playback. That's what it's for.

br777, if even unity gain is too much for you, you can make divider on amp's input. Change R3,R7 to 10k - 30k, this make voltage divider with R14,R20.
Or simplest way to try - just connect 10K-30K resistors between ODAC output and amp input (instead wires)